Rotary salt bath furnaces



June 1964 B. R. ANKERSEN 3,137,752

ROTARY SALT BATH FURNACES Filed Dec. 10, 1958 2 Sheets-Sheet 1 Fig.!

Fig.2.

m VEN TOR.

l6 I3 I Borge Richard Ankersen HIS ATTORNEYS United States Patent3,137,752 ROTARY SALT BATH FURNACES Borge Richard Anlrersen, R0. Box989, Butler, Pa.

Filed Dec. 10, 1958, Ser. No. 779,319 I 9 Claims. (Cl. 266-4) receivingmetal articles to be heated, carrying those articles through a heatingmedium out of contact with the atmosphere or corrosive gases anddischarging the heated objects after they have attained the desiredtemperature level. Various types of travelling hearth furnaces have beenproposed for heating metal objects. However, they have either permittedthe products of cornbustion and the atmosphere or both to be in contactwith the articles or they have required special gaseous atmospheres inorder to avoid contact with the atmosphere and corrosive gases.

I have invented a furnace and a method of heating metal articles whicheliminates these problems and provides means for heating metal objectsfree from the corrosive influences of furnace gases or atmosphere. Iprovide a container pivotally mounted for rotation onits bottom, meansfor rotating the container about said pivotalmounting, a bath of salt insaid container below the level of the top thereof, a housing suspendedabove said container and extending into the bath of salt about theperiphery spaced from the walls of the container whereby to form anaccess opening between the container and the periphery of the housing,heating means in the housing in a position to act upon the bath of salt.Preferably, the container is a saucer shaped refractory pot mounted forrotation at its axis and carrying wheel members adjacent its peripheryfor support thereof during'rotation. Preferably, the housing over thepot is a frusto-conical refractory member whose edges dip beneath thesurface of the salt at a point spaced from the inner wall of the pot. Ina preferred form burner means are provided in the housing in a positionto direct its flame onto the upper surface of the bath of salt andoutlet means are provided in the housing spaced from the bath for egressof combustion gases. Preferably, this housing is supported by supportingmembers extending over the top of the pot at a point outside theperiphery of the pot whereby the pot is free to rotate with respect tothe housing. Means are preferably provided spaced apart along theperiphery of the pot for loading or unloading the articles to betreated.

In the foregoing general description, I have set out certain objects,purposes and advantages of my invention. Other objects, purposes andadvantages will be apparent from a consideration of the followingdescription and the accompanying drawings inyvhich,

FIGURE 1 is a top plan view of a preferred form of my invention;

FIGURE 2 is a side elevation of the furnace shown in FIGURE 1;

FIGURE 3 is a section on the line III-III of FIGURE 1; and l FIGURE 4is. a transverse section through a second embodiment of my invention.

. Referring to the drawings Ihave illustrated a preferred form of myfurnace having a saucer shaped pot made up of radially extending basemembers 11 connected together at the center on a pivot pin 12 rotatablein a hollow supporting member 13 on ball bearings 14. The other ends ofthe radial members 11 are provided with wheels 15 rotatable on thecircular track 16. Angularly extend- 3,137,752 Patented June 16, 1964rce ing beams 17 are fixed to the radial members 11 adjacent each endand are held rigidly in position by vertical supports 18. The members 11and 17 form a generally saucer shaped framework which supports arefractory bowl made up of brickwork 19 and a refractory lining 20. Acircular rack gear 21 surrounds the pot and is attached to thesupporting members 17 adjacent and connected with vertical supports 18.The rack is driven by a pinion gear 22 connected to an electric motorthrough a gear train, not shown. A supporting framework 23 is mounted onvertical legs 24 lying outside the periphery of the pot Ill andsupported on the working floor 25. The members 23 extend over pot 10 andare spaced therefrom. A

frusto-conical housing 26 is suspended from supporting members 23 byroof supports 27. The housing 26 communicates with a stack28 whichextends vertically above the axis of the pot 10. Burners 29 are mountedin the housing 26 to be directed angularly towards the refractory hearth20. Preferably, the hearth 20 has an inner generally conical elevatedcentral portion 30 over which the salt bath 31 extends. The lower edge26a of the housing extends beneath the surface of the salt and is spacedfrom hearth 20 to provide an opening 32 into the salt 31. A conveyor 33is preferably provided at a tangent to theperiphery of the furnace tocarry articles to be treated to the edge of the hearth 20. Anhydraulically operated load arm 34 is mounted adjacent the circumferenceof hearth 20 and is adapted to push an object 35 to be treateddownwardly along the hearth wall 20 to the position shown in dottedlines on FIGURE 3. An unloading arm 37 is mounted on the framework 23and is adapted to rest beneath the surface of the bath 31 and to engagethe end of an article being treated by a hook member 37a, draw thearticle 36 upwardly along the hearth wall 20 and to discharge onto aconveyor 38.

The operation of my invention is as follows. The bath 31 is heated bythe flames from burners 29 to the desired high temperature molten state.Articles to be treated'are loaded on the hearth 20 by the loading arm 34as the hearth is rotated about the pivot pin 12 on wheels 15 by the rackand pinion 21, 22. As the hearth rotates the articles to be treated36are heated to the desired temperature and carried to the position wherethe unloading arm 37 can engage them and draw them out of the bath ontoconveyor 38. Articles are thereafter continuously loaded by the loadingarm 34 and unloaded by unloading arm 37 as the hearth slowly rotates.

Referring to the embodiment illustrated in FIGURE 4, I have shown asaucer shaped pot 50 made up of radially extending base members 51connected together at the center on a pivot pin 52 rotatable in a hollowsupporting member 53 on ball bearings 54. The outer ends of the radialmembers 51 are provided with wheels 55 rotatable on a track 56.Angularly extending beams 57 are fixed to the radial members .51adjacent their outer ends and held rigidly by vertical members 58; This;framework supports a refractory bowl 59. A circular rack gear 60surrounds the pot and is attached to supports 57. The rack 60 is drivenby a pinion 61 connected to a motor, not shown. A supporting framework62 is mounted on legs 63 outside the pot and resting on work floor 64..A frusto-conical housing 65 is suspended from framework 62 over thecenter of the pot 50 and the edge of the housing extends beneath thesurface of the pool of salt 66. Electrodes 67 pass through openings 68adjacent the center of the housing into the pool of salt. Electrodes 67are energized from a conventional source of electrical energy by meansof the conventional connections and these are accordingly notillustrated. The operation of the furnace is identical with that ofFIGURES 1 through 3 a 3 except for the source of heat energy deliveredto the salt pool.

While I have illustrated a present preferred embodiment of my invention,it will be distinctly understood that this invention may be otherwiseembodied within the scope of the following claims.

I claim:

1. A salt bath furnace comprising a pot adapted to be pivoted about apoint on the bottom thereof, drive means adapted to rotate said potabout said point, a bath of salt in said pot below the level of the topof the pot, an open bottom housing covering a portion of the surface ofsaid salt and spaced from the periphery of the pot, said housingextending beneath the surface of the salt in sealing relationship aroundits periphery forming a separate heating chamber, burner means in saidhousing and outlet means in the housing permitting egress of combustiongases from the housing at a point spaced from the periphery in thehousing.

2. A salt bath furnace comprising a pot adapted to be pivoted about apoint on the bottom thereof, drive means adapted to rotate said potabout said point, a bath of salt in said pot below the level of the topof the pot, an open bottom housing suspended above said pot andindependent'thereof covering a portion of the surface of said salt andspaced from the periphery of the pot, said housing extending beneath thesurface of the salt in sealing relationship around its periphery forminga separate heating chamber, burner means in said housing and outletmeans in the housing permitting egress of combustion gases from thehousing at a point spaced from the periphery of the housing.

3. A salt bath furnace comprising a saucer shaped pot adapted to bepivoted on its axis, drive means adapted to rotate said pot about itsaxis, a bath of salt in said pot below the level of the top of the pot,an open bottom generally frusto-conical housing covering a portion ofthe surface of said salt, the outer bottom periphery of said housingextending beneath the surface of the salt in sealing relationship spacedfrom the inner wall of the pot,

forming a separate heating chamber, burner means in said housing andoutlet means in the housing permitting egress of combustion gases fromthe housing at a point spaced from the periphery of the housing.

4. A salt bath furnace comprising a saucer shaped pot adapted to bepivoted on its axis, drive means adapted to rotate said pot about itsaxis, a bath of salt in said pot .below the level of the top of the pot,an open bottom generally frusto-conical housing covering a portion ofthe surface of said salt, the outer bottom periphery of said housingextending beneath the surface of the salt in sealing relationshp spacedfrom the inner wall of the pot forming a separate heating chamber,burner means in said housing directed generally onto the surface of thebath and an outlet means at the apex of the housing permitting egress ofcombustion gases from the housing.

5. A salt bath furnace comprising a saucer shaped pot adapted to bepivoted on its axis, rack means on the pot spaced radially from the axisthereof, pinion drive means in driving engagement with said rack, a bathof salt in said pot below the level of the top of the pot, an openbottom housing covering a portion of the surface of said salt and spacedfrom the periphery of the pot to form a separate work opening into thepot, the open periphery of said housing extending beneath the surface ofthe salt in sealing relationship to form a separate combustion chamber,burner means in said housing and outlet means in the housing permittingegress of combustion gases from housing. v

6. A salt bath furnace comprising a saucer shaped pot adapted to bepivoted on its axis, rack means on the pot spaced radially from the axisthereof, pinion drive means in driving engagement with said rack, a bathof salt in said pot below the level of the top of the pot, an openbottom housing suspended above the pot and independent thereof, saidhousing covering a portion of the surface of said salt and spaced fromthe periphery of the pot to form a separate work opening therebetweeninto the pot, the open periphery of said housing extending beneath thesurface of the salt in sealing relationship 'to form a separatecombustion chamber, burner means in said housing and outlet means in thehousing permitting egress of combustion gases from the housing at apoint spaced from the periphery of the housing. I

7. A salt bath furnace comprising a pot adapted to be pivoted about apoint on the bottom thereof, drive means adapted to rotate about saidpoint, a bath of salt in said pot below the level of the top of the pot,an open bottom housing covering a portion of the surface of said saltand spaced from the periphery of the pot, said housing extending beneaththe surface of the salt in sealing rela-.

tionship around its periphery forming a separate combustion chamber,burner means in said housing, outlet means in the housing permittingegress of combustion gases from the housing at a point spaced from theperiphery of the housing, work feed means adjacent the periphery of thepot adapted to insert work to be treated into the saltbath and Workremoval means adjacent said work feed means adapted to remove the workfrom said pot after rotation from the work feed means.

8. A salt bath furnace comprising a pot adapted to be pivoted about apoint on the bottom thereof, drive means adapted to rotate said potabout said point, a bath of salt in said pot below the level of the topof the pot, an open bottom housing covering a portion of the surface ofsaid salt and spaced from the periphery of the pot, said housingextending beneath the surface of the salt in sealing relationship spacedfrom the pot and forming a heating zone therein and heating means insaid housing adapted to introduce heat into the salt in said heatingzone.

9. A salt bath furnace comprising a pot adapted to be pivoted about apoint on the bottom thereof, drive means adapted to rotate said potabout said point, a bath of salt in said pot below the level of the topof the pot, an open bottom housing covering a portion of the surface ofsaid salt and spaced from the periphery of the pot, said housingextending beneath the surface of the salt in sealing relationship spacedfrom the pot and forming a heating zone therein, spaced heatingelectrodes extending into said bath of salt beneath said housing andconnections from a source of electrical energy to said electrodeswhereby said salt may be heated.

References Cited in the file of this patent UNITED STATES PATENTS1,628,012 Tracy May 10, 1927 p 2,168,028 Harsch Aug. 1, 1939 2,477,561Holden Aug. 2, 1949 2,542,637 De Poy Feb. 20, 1951 2,611,693 Geyer Sept.23, 1952 2,618,284 Purnell Nov. 18, 1952 2,697,596 Troglione Dec. 21,1954 2,738,294 Sperce Mar. 13,1956 2,816,849 Ankersen Dec. 17, 19572,845,260 Rusciano July 29, 1958 2.888.506 Harris May 26. 1959

1. A SALT BATH FURNACE COMPRISING A POT ADAPTED TO BE PIVOTED ABOUT APOINT ON THE BOTTOM THEREOF, DRIVE MEANS ADAPTED TO ROTATE SAID POTABOUT SAID POINT, A BATH OF SALT INSAID POT BELOW THE LEVEL OF THE TOPOF THE POT, AN OPEN BOTTOM HOUSING COVERING APORTION OF THE SURFACE OFSAID SALT AND SPACED FROM THE PERIPHERY OF THE POT, SAID HOUSINGEXTENDING BENEATH THE SURFACE OF THE SALT IN